Hericium erinaceus

This delicious mushroom has been referred to as 'Nature's Nutrient for the Neurons' on account of its ability to stimulate the production of nerve growth factor (NGF)1,2.

NGF plays an essential role in the differentiation and survival of several nerve cell populations in the central and peripheral nervous system and lower than normal levels of NGF have been shown to be linked to early stages of both alzheimers disease and dementia3-8.

Although therapeutic interest has largely focusssed on its importance for neurological function, NGF has a much wider role in maintaining homoeostasis in the body9,10. It is known to have insulinotropic, angiogenic, and antioxidant properties and reduced plasma levels of NGF have been associated with cardiovascular diseases and metabolic syndromes, including type 2 diabetes11,12. It has been shown to accelerate wound healing and there is also evidence that it could be useful in the treatment of skin and corneal ulcers13. Animal studies have shown NGF to have a profound effect on airway inflammation and asthma-related symptoms with increased NGF levels observed in bronchoalveolar lavage fluid and serum from patients with asthma14.

NGF also has a dynamic relationship with the immune system. Production of NGF is increased after brain injury, in part due to cytokines produced by immune cells. At the same time cells of the immune system express receptors for NGF, which is involved in immune modulation15.

Two families of cyathane derivatives from H. erinaceus have been identified as being active in the stimulation of NGF production: the hericenones (isolated from the fruiting body) and the erinacines (isolated from the mycelium). Critically these molecules are small enough to pass through the blood-brain barrier. There is also evidence that they can increase myelination1,16,17.

In China the mycelium is used to make Hericium erinaceus Pills to treat gastric and duodenal ulcers, chronic gastritis, gastric and oesophageal cancer.

Dementia - In controlled studies H. erinaceus supplementation showed beneficial effects in patients with mild dementia. In one study 6 out of 7 patients showed improvement in functional capacity (understanding, communication, memory etc.) while all 7 showed improved Functional Independence Scores (eating, dressing, walking etc.), after consuming 5g H. erinaceus fruiting body daily in soup1. In another study, 30 patients aged 50-80 with mild dementia were randomised into treatment and control groups. H. erinaceus was given as tablets at 3g/day for 16 weeks and produced significant increases in cognitive function in the treatment group. However, four weeks after the conclusion of the trial, cognitive function scores decreased17.

MS - H. erinaceus fruiting body extract has been shown to improve the myelination process in mature myelinating fibers with possible benefits for MS patients18,19. NGF has also been shown to have a protective effect on axons and myelin by suppressing the immune-mediated inflammatory processes responsible for chronic brain destruction in neurodegenerative disorders such as MS by switching the immune response to an anti-inflammatory, suppressive mode in a brain-specific environment13.

Neuropathy - NGF plays a role in pain sensitivity and low NGF levels have been linked to sensory neuropathy in both in vivo and in vitro studies10. Enhanced NGF production has been shown to protect sensory function in diabetic rats and NGF reduction has been shown to cause cardiac sensory neuropathy21,22.

Clinical studies with recombinant human nerve growth factor indicate benefit in patients with diabetic polyneuropathy23 and NGF has also been reported to reduce pain in patients with HIV associated sensory neuropathy24,25. However, ability to promote regeneration of sensory neurons has yet to be demonstrated26,27.

MRSA - Extracts of both fruiting body and mycellium exhibit anti-MRSA activity with erinacines identified as active compounds. In clinical tests in Japan MRSA is reported to have disappeared in a percentage of patients whose diet was supplemented with H.erinaceus29.

GASTRITIS - One of the traditional indications for H. erinaceus, it appears likely that its beneficial effects in this regard are also a function of the antibacterial action of its cyathane derivatives, with Helicobacter pylori now known to be a major cause of chronic gastritis30-32.

CLINICAL SUMMARYMain Therapeutic Application - Dementia, Alzheimers and Nerve Damage. May have benefit for MS but clinical evidence lacking.Key Component - Cyathane derivatives including hericenones and erinacinesDose - Clinical trials support the use of dried fruiting body at a dose of 3-5g/day for increasing NGF production while animal studies on the use of H. erinaceus for gastric ulcers produced the best results with a daily intake of 500mg/kg, which equates to the dosage prescribed in the Chinese Phamacopoeia of 25-50g/day32,33. It is likely that similar doses would be required in cases of MRSA.

High in-vitro NGF promoting activity of mycellial extracts and the fermentation broth also indicates potential use of biomass products in this regard34,35.

Caution - Asthma and other allergic conditions. Erinacine E is a potent agonist of the Kappa opioid receptor with potential hallucinogenic properties36.